See attached graphic. Triangle ABC is a 45 45 90 triangle. Side AB = Side BC = hypotenuse * (1 / sq root (2) ) SIde AB = BC = 10 *
0.7071067812
SIde AB = BC = 7.071067812 Area of Triangle ABC = (AB * BC) / 2 Area of Triangle ABC = 25 Area of Triangle DEF = 25 Line FB = 10 Line FD = 7.071067812 Area of Rectangle FBDA = 70.71067812 Total Area of Shaded Area = 25 + 25 + 70.71067812 = 120.71067812
